It is very often desirable to have underwater illumination in a swimming pool, for use at night, for special effects or simply for purposes of safety. This may be so even in commercial pools such as recreational pools which may be municipally or privately owned, pools in such establishments as health clubs and hotels, and pools which may be specially constructed for competitive purposes of swimming or diving. As well, many private owners of swimming pools desire to have underwater illumination in their pools. Normally, in the past, illumination in a swimming pool -- whether it be private or commercial -- has comprised a special lamp housing assembly which is fitted into the wall of the pool at the time that the pool is being constructed. Such lighting assemblies are intended to be operated from ordinary household power supplies -- in North America, 108 to 120 volts at 60 hertz -- and the lamp units are generally very high powered, incandescent lamps having power consumptions of from 350 to 750 watts. The light output from such units is of course very high; and most prior art swimming pool illumination systems have operated very hot. Thus, there is a slight danger of breakage if such a unit is turned on when the water in a swimming pool is extremely cold, and there is also a danger of a swimmer in the pool being burned by touching the unit. In addition, serious electrical hazards exist with the prior art underwater swimming pool illumination systems.
The most obvious electrical hazard which exists is of course, one of electrical shock. Stray currents may occur from any conventional underwater lighting assembly; and such stray currents may, of course, prove to be fatal if they are impressed on the body of a swimmer or even a person in the immediate area of a swimming pool. As a consequence, conventional underwater lighting assemblies which are installed in swimming pools require to be grounded, as well as all other metallic parts which may be installed in a pool such as ladders and the like; and also all metallic parts within ten feet of the surface of the water of the swimming pool are required to be grounded in most jurisdictions. Further, it is necessary for a ground fault detector to be installed, which shuts the system off in the event of any leakage current from either side of the two wire electrical supply to the conventional underwater swimming pool illumination assemblies, to ground. Of course, the effectiveness and safety of such equipment relies upon it being continuously inspected for consistency of operation.
Apart from the evident high costs of conventional underwater illumination lighting assemblies, yet another disadvantage exists, especially for owners of existing pools and persons who are installing new private pools which may be of the variety having steel walls and a vinyl liner. That is, in many smaller pools of the sort which are installed in private homes, the construction comprises a relatively thin sheet steel wall and a preformed vinyl liner installed within the pool. Because of their physical bulk, conventional underwater swimming pool lighting assemblies are difficult to install in vinyl-lined in-ground pools. As well, the cost of installing a conventional underwater lighting assembly in any swimming pool -- whether it be vinyl lined, or with more conventional concrete walls -- may be extremely high. This may be all the more difficult in circumstances where a deck or patio has been built around the periphery of the swimming pool, and where other matters of landscaping and decoration have been completed.
It has been noted, however, that it is possible to achieve a reasonable or satisfactory degree of illumination within a swimming pool with lighting assemblies having relatively low power consumption. That is, in a conventional private pool of, say, 16 feet by 32 feet or even 20 feet by 40 feet, and having a depth from 8 to 9.5 feet, low voltage lamp units having rated powers of from 25 to 35 watts, used either singly or in association with one or two other such units, provide quite adequate underwater illumination. Power for such lamp units may be derived from low voltage, direct current batteries of even modest ratings. In addition, it is possible to provide electrical connections to a low voltage battery -- say, of 12 volt rating -- in such a manner that the battery may be part of a self-contained lighting assembly, or be remotely mounted away from the immediate area of a swimming pool; and be connected in such a way that if the battery is electrically connected to a battery charging circuit, it is completely electrically isolated from the lamp unit of the lighting assembly so as to completely preclude alternating current hazards. It has been shown that stray alternating currents at even very low voltages may be fatal if the circumstances surrounding the manner in which they are induced upon a person's body are particularly unfortunate. Thus, for the sake of safety of any persons in or near a swimming pool having underwater illumination, and for relative ease of assembly and maintenance -- not to mention economies both with respect to capital costs and operation -- this invention provides that underwater lighting assemblies of the sort taught herein are powered by low voltage direct current batteries so as to provide a low voltage, ripple-free direct current power to the lamp unit of any lighting assembly according hereto.
In like manner, it has been determined that for purpose of decor, as well as ease and economy of production and of installation, an underwater lighting assembly according to this invention can be provided where such assembly is such that it may be easily lifted into and out of the water of a swimming pool. That is, at least the waterproof lamp enclosure of a lamp assembly of this invention may be such that it can be installed in, attached to or placed beside the wall of a swimming pool and easily removed therefrom. In the preferred embodiments of this invention as described herein, underwater lighting assemblies are provided wherein a base may be secured to a pad which is, in turn, secured to the deck of a swimming pool; and where a strut having a waterproof lamp enclosure in the lower portion thereof depends downwardly from one end of the base into the water of the swimming pool, so that the lamp unit in the lamp enclosure is below the surface of the water.
The waterproof lamp enclosure which is provided by this invention has a generally bowl-shaped body portion which is adapted to receive the rear portion of a conically shaped lamp unit -- usually a sealed beam unit having a rating of from 25 to 35 watts. An O-ring seat is formed in the bowl-shaped body portion, and a compressible O-ring is fitted into the O-ring seat. A retainer is provided, together with suitable fastener means which are adapted to co-operate with a flange formed around the outer part of the bowl-shaped body portion, so that when the fastener means are tightened, the retainer means forces the conical-shaped rear portion of the lamp unit against the compressible O-ring. In the preferred embodiments, the retainer is a light diffracting lens ring which co-operates with the outer portion of the lamp unit.
Electrical wires which are attached to the lamp unit and which lead to a low voltage battery pass rearwardly from the body portion; and the rear of the body portion of the waterproof lamp enclosure is exteriorally waterproofed. This may be by use of a seal or a packing gland; and in the preferred embodiments, by sealing the strut in which the waterproof enclosure is formed so that interior of the strut is, itself, waterproofed. Also, the interior by the strut may be filled, at least in its lower portion with a foamable plastics material.
Because of its construction, a waterproof lamp enclosure according to this invention is essentially water-cooled when operating. All of the assembly in front of the O-ring is immersed in water, and the rear of the assembly is dry. In the preferred embodiments, the lamp assembly itself is immersed. In any event, it is possible to use plastics materials for all of the major structural components of a lighting assembly according to this invention without any risk of failure due to heat, and without electrical leakage.
The preferred embodiments of this invention provide two approaches to lighting assemblies for use in swimming pool underwater illumination systems, whereby the lighting assembly may either be self-powered -- that is, having batteries enclosed within its structure -- or where the lighting assembly may be remotely powered. Thus, with a minimum of additional requirement and a maximum interchangability of parts, self-powered or remotely powered lighting assemblies may be easily and economically produced and installed.